Big Earth Observation Data and Web GIS applications€¦ · Big Earth Observation Data and Web GIS...
Transcript of Big Earth Observation Data and Web GIS applications€¦ · Big Earth Observation Data and Web GIS...
Big Earth Observation Data and Web GIS applications
Monitoring Earth’s Surface Water from Space
Data, Tools, and Algorithms
Gennadii Donchyts
Satellite Sensors and Measurements
DN Spectral Radiance Radiance Reflectance
Visible and invisible colors
Gorelick et.al., 2017, Remote Sensing of Environment
https://developers.google.com/earth-engine/datasets/
~20 Petabytes of data
Earth Engine
Storage and Compute
Landsat Satellite Data
Landsat images per year
1 50
cloudsshadows
TO
A r
efle
ctan
ce, %
Percentiles, %
clear pixels
10% 62%
cloudsshadows
TO
A r
efle
ctan
ce, %
Percentiles, %
clear pixels
Actual images vs. Reflectance Percentile Composites
http://www.earthenv.org/cloud
New Land New Water
Tools used App Engine (PaaS) Google Earth Engine API Google Maps API HTML / JavaScript
http://aqua-monitor.deltares.nl
Reservoir Monitoring
http://bit.ly/global_reservoirs_map_2016 GRanD ~= 6000, HydroLAKES ~= 1mln
Reservoirs
work in progress …
Combine multiple reservoir datasets (HydroLAKES)
Derive surface water area dynamics
Estimate storage
Reservoirs / Lakes
Donchyts, 2018, PhD Thesis
Discriminative vs. Generative
Water Mask vs. Water Occurrence vs. Water Changes vs. Underwater
0
1000000
2000000
3000000
4000000
14-11-1984 7-5-1990 28-10-1995 19-4-2001 10-10-2006 1-4-2012 22-9-2017
Surface water area estimated from satellite and from local water level station
* after outlier removal 0
2000000
4000000
0 2000000 4000000
A* (A)
RMSE < 0.059 km2
A = 0.5 – 3 km2
R2 = 0.991
Coastal Bathymetry
In-situ measurements Derived from satellites
Reconstructed inverse-depth bathymetry
Reservoirs
Coastal Areas
Rivers
Reservoirs
Lakes
Waterbody Types
Questions
How to harmonize all water datasets?
How to monitor surface water changes globally at 1m resolution?
How can we stop using Web Mercator (only) in Web Maps?
How to make Web GIS maps 4D?
How to mix satellite images, vector datasets and point clouds?
How to stream video in Web GIS?
What kind of web-based analysis tools are missing?